Many people would wear headphones to listen to music. Differently configured headphones are available, such as in-ear headphones, clip-on earphones, and headband headphones.
Headphones can also be classified according to the technical methods they employed to reproduce or generate sound. For example, there is a type of electrostatic headphones, which can be further divided into DC-bias voltage headphones and electret headphones according to the working principle thereof. According to the working principle of the DC-bias voltage headphones, a DC (direct current) bias voltage is continuously applied across each of the diaphragms of the headphones, so that charges are distributed over the entire diaphragm; meanwhile, two AC (alternating current) voltages of opposite phases are synchronously and continuously applied across two perforated metal plates located at two opposite sides of the diaphragm. Electrostatic forces produced by positive and negative charges bring the diaphragm to vibrate and output sound. On the other hand, according to the working principle of the electret headphones, the diaphragms thereof are charged before product assembling, so that charges are distributed on the diaphragms and it is not necessary to apply any DC bias voltage signal across the diaphragms when using the electret headphones; meanwhile, two AC (alternating current) voltages of opposite phases are synchronously and continuously applied across two perforated metal plates located at two opposite sides of the diaphragm. Electrostatic forces produced by positive and negative charges bring the diaphragm to vibrate and output sound. Since the working principles of the DC-bias voltage headphones and the electret headphones are known to those skilled in the art, they are not discussed in details herein.
Conventionally, the sound-generating assemblies for electrostatic headphones are manufactured by hot-press molding. That is, the diaphragms, spacers, perforated plates, and other external components, such as ear cups, included in the electrostatic headphones for generating sound are completely assembled by hot-press molding. However, while the hot-press molding process enables automated and efficient production, the hot-press molded sound-generating assemblies do not allow disassembling for the purpose of replacing any components that are found defective in a sound quality test. The hot-press molded sound-generating assemblies, once disassembled, would become entirely unusable. As it is known, the diaphragms used in the electrostatic headphones are very expensive. It is apparently not economical if the expensive diaphragms are discarded along with other components when the hot-press molded sound-generating assemblies fail to pass the sound quality test. Therefore, the conventional sound-generating assemblies for electrostatic headphones manufactured by hot-press molding disadvantageously have risks of high assembling and manufacturing costs and could not be conveniently maintained or repaired.
It is therefore tried by the inventor to develop a headphone sound-generating structure and a method of assembling same, so that the headphone sound-generating structure can be quickly assembled at lowered cost and increased good yield, and can be conveniently maintained without wasting any material.